The present invention relates to a method of manufacturing a hydrogen storage tank and to a hydrogen storage tank.
Over the recent years, a scheme for reducing carbon dioxide has so far involved using a hydrogen gas, an LPG (Liquid Petroleum Gas), a CNG (Compressed Natural Gas), etc as a fuel for an automobile etc. A requirement for these fuel gasses is that the fuel gasses can be stored in a gas tank and can be emitted for utilization when a necessity arises. Known as a method of storing the hydrogen gas is, for example, a technology of filling an interior of the tank with hydrogen-occlusion alloys and getting the hydrogen occluded by the filled hydrogen-occlusion alloys. This type of technology enables the hydrogen gas to be stored in a way that gets the hydrogen gas occluded by the hydrogen-occlusion alloys and to be utilized as a fuel by getting the hydrogen gas emitted from the hydrogen-occlusion alloys.
The hydrogen-occlusion alloys have a characteristic of expanding as the alloys occlude the hydrogen gas and contracting as the hydrogen gas is emitted therefrom. As a result, there arises a problem that the hydrogen-occlusion alloys precipitate, i.e., concentrate on one side (a deviation in density) in the tank due to the expansion and the contraction of the hydrogen-occlusion alloys. Another problem is that if the hydrogen is occluded in a state where the hydrogen-occlusion alloys concentrate on one side, i.e., get consolidated, an excessive stress occurs locally due to the expansion. Such being the case, a variety of technologies have been developed for solving these problems.
For example, Patent document 1 discloses a technology of adding a binder to the hydrogen-occlusion alloys into a paste state and, after coating the paste-like hydrogen-occlusion alloys over metal porous sheets, then forming hydrogen-occlusion sheets by pressurization, and laminating the sheets. Further, for example, Patent document 2 discloses a technology related to the hydrogen storage tank in which a body interior of the hydrogen storage tank is sectioned into a plurality of air spaces, and, after forming the sectioned air spaces, the sectioned air spaces are respectively filled with the hydrogen-occlusion alloys.
[Patent document 1] Japanese Patent Laid-Open Publication No. 2001-241599
[Patent document 2] Japanese Patent Laid-Open Publication No. 2004-162885
[Patent document 3] Japanese Patent Laid-Open Publication No. 2005-240983
[Patent document 4] Japanese Patent Laid-Open Publication No. 2005-105329